Wetlands face long recovery

    One of the six helicopters attending the Awarua Bay scrub fire dowses the flames during the weekend. Photo: Toni McDonald

    THE 32mm of rain overnight on Tuesday brought a sigh of relief for many around the province as empty water tanks refilled and parched land received some longed-for moisture.

    While the rain gave the 30 firefighters at the Awarua bush fire scene some relief, high winds with gusts up to 100kmh had grounded the helicopters, Fire and Emergency NZ (Fenz) incident controller Mark Mawhinney said.

    MetService meteorologist Peter Little said many coastal areas had received 29-32mm of rain. But the inland regions had only received 6-10mm.

    A 1350ha portion of the Awarua Wetlands was engulfed by fire fuelled by high winds and parched scrub about 5.45pm on Saturday. It was unknown how the inferno started but
    investigations into the cause were continuing.

    Firefighters had been on the scene since early on Saturday evening fighting the wetlands blaze with multiple helicopters and ground crews.

    Fenz efforts to battle the blaze were initially hampered when darkness fell on Saturday evening, leaving staff only able to watch as the fire developed a 26km perimeter to be tackled at first light on Sunday.

    Mr Mawhinney said he was pleased with the progress air and ground crews had made.

    ‘‘They have done an amazing job in some challenging conditions.’’

    Rain on Tuesday evening had extinguished the top burning portion and penetrated 5-10cm into the peat-bog, significantly dampening the fire. But the fire, seated deep in the peat,
    was still active.

    Fenz had initially believed it could take several weeks to fully douse the fire.

    Mr Mawhinney said the high winds and cooler temperatures had now produced a different challenge for the ground crews and expected to stand down the crews if the weather worsened.

    Environment Southland (ES) integrated catchment management general manager Paul Hulse said ES was concerned a fire had taken hold in the Awarua-Waituna wetlands which had international significance and for the loss of flora and fauna.

    Forest and Bird’s freshwater advocate Tom Kay said the organisation was devastated to see the Southland wetlands burning.

    Most years Awarua Bay was home to more species than any other place in Southland.

    University of Otago Emeritus Professor Sir Alan Mark said fire was the worst thing that could happen to any wetland. They were hard to put out and the combustion converted the
    stored carbon to carbon dioxide, a major greenhouse gas. He believed it would take years for the burned wetland to recover.

    ‘‘A season with little rain has contributed to a much lower water table, making the peat much more flammable.’’

    Widespread water restrictions and irrigation bans have been in place across Southland as councils called for all residents to do their bit to conserve water as rivers dried up.

    The ES website showed many rivers had reached critical levels across Southland and Otago.

    But the overnight rain on Tuesday had a minimal impact on increased flows, with most remaining well below their normal flow rates.

    The Oreti and Mataura rivers, which had been flowing well below their normal levels, had received between 11-28mm rain in their headwaters.

    An ES spokesperson said it would take a little time for the full effects of the rain to be seen.

    ‘‘The rivers are responding slowly and we expect to see some more movement later in the day (yesterday).’’

    ES would be doing a full review of the river levels today to discuss if the present irrigation bans in place would remain or could be removed.

    ‘Extremely valuable’
    THE Awarua-Waituna wetlands are home to many threatened plants and insects, including sub-alpine species uniquely found at sea-level.

    More than 80 bird species had been recorded there, Forest and Bird freshwater advocate Tom Kay said.

    ‘‘Only about 10% of Aotearoa’s historic wetlands remain — most have been drained for agriculture or the development of towns and cities. So those wetlands that remain are incredibly rare and incredibly important.’’

    University of Otago Emeritus Professor Sir Alan Mark said Awarua-Waituna was one of the few remaining large wetlands helping to protect the country against climate change with its
    major carbon storage.

    ‘‘Wetland ecosystems offer unparalleled carbon storage, and the depth of peat in Awarua-Waituna is substantial. It is an extremely valuable ecosystem and has unique biodiversity. It is the only place in the country with an intriguing collection of alpine wetland plants near sea-level.’’

    The western edge of the wetlands was a prime area for fire to break out — especially in dry weather, he said.

    Peat wetlands hold twice as much carbon as all of the world’s forests combined, despite only covering 3% of the Earth’s land surface, and coastal wetlands can store carbon 35-57 times faster than tropical forests.

    ‘‘They also create a local cooling effect and increase climate resilience by buffering communities from storm surges and floods.’’

    Peat became a massive emitter of greenhouse gases when it dried out or became degraded and the carbon it stored could fuel raging fires.